1. Field of the Invention
This invention relates to a method for improving the efficiency of an electrical power generation system. More specifically, a power source, which includes at least one battery comprising an anode and a liquid electrolyte that contains solid particulate, is integrated with a solids separation means. The solid separation means comprises an impeller, a container having an axis and inlet and outlet means. This system provides for the highly effective continuous separation of solid particulate from the electrolyte resulting in high efficiency in electrical power generation.
2. State of the Art
The operation of certain energy or power generation systems commonly utilized a recirculating liquid. Inherent in some of these systems is the possibility of a build up of solid discharge products. Thus, in metal/air batteries, which typically use a recirculating alkaline electrolyte, a metal oxide discharge product accumulates in the electrolyte. One such system is taught in U.S. Pat. No. 4,246,324, wherein spent electrolyte containing precipitated oxides may simply be removed from the battery container through a draining nozzle.
It has been recognized, such as in U.S. Pat. No. 3,359,136, that complete energy conversion systems may employ means for separating the metal oxide from the recirculating electrolyte. As discussed in this patent, oxide removal can maintain the concentration of the oxide reaction product in the electrolyte at a sufficiently low level for recirculation of electrolyte to a power source, such as a cell stack. As also disclosed in the patent, a separator can be useful to treat a portion of recirculating electrolyte. Such separator can constitute a self-cleaning filter, although the filter may require periodic scraping.
It is disclosed in U.S. Pat. No. 3,708,345, that the mechanically separated oxide reaction product may be conveniently stored near a mechanical separator apparatus for eventual removal. As more fully discussed therein, the suspended zinc oxide reaction product which is separated, can find use as in recharging the zinc electrodes.
Impeller-fluidizers have been proposed for mixing and separating, e.g., separating at least one liquid of different densities. In U.S. Pat. No. 3,129,066 such an apparatus, containing a perforate, generally cone-shaped, solids accumulating barrier within the fluidizer container, is taught as useful for the separation of at least one solid of different density from an entraining liquid.
Also, as in U.S. patent application Ser. No. 843,055 of M. A. Petrick et al, there is described an impeller-fluidizer apparatus that can be useful for separating an entrained solid in a slurry fed to the apparatus. A product high in particulate concentration as well as one of very low particulate concentration may be produced, particularly in a cascading series of discrete fluidizer elements.
It would nevertheless be desirable if an entire power source and solids discharge separation system could be integrated to handle the continuous separation of solid particulate from the electrolyte to provide enhanced and efficient energy generation from metal/air batteries. It would also be desirable if such separator system for solids removal could operate most economically at low power requirements while integrated into such a continuous flow operation system that is operating with copious amounts of recirculating electrolyte. It would furthermore be advantageous if the system could not only operate on a continuous basis, but could do so without frequent interchange of critical elements, e.g., without interchange of used filters.